“WASHINGTON — Law enforcement officials said on Tuesday that they had opened an investigation into a Web site that posted the home addresses, Social Security numbers and other personal information for more than a dozen celebrities and politicians, including Vice President Joseph R. Biden Jr., Michelle Obama and Jay-Z.

“At this point, we are trying to determine the sourcing of this and the validity of the stuff that is being posted,” said a senior federal law enforcement official.

The investigation is being led by the Federal Bureau of Investigation, the Secret Service and the Los Angeles Police Department, law enforcement officials said.”